Oh hey, an old question that went unanswered.
The main trick to this room:
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×The NPC moves south whenever you move directly south. Otherwise, he doesn't move. You can move southwest or southeast and keep him in place.
He also moves after the monsters, which is important to keep in mind. This allows you to make a stable setup:
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×Stand in the row north of the NPC. When the tar baby is to the NPC's northwest, move south; the baby will move one south because the NPC is in the way and then the NPC will move south, so their relative positions remain unchanged.
If you need a little more help after that:
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×After a while, all the monsters will be lined up in a row. So, move southeast or southwest to get them stuck behind the citizen NPC once they're in a row that the guard NPC will stab.
